A/C had stopped blowing cold the compressor not turning on?

Tiny
SHANE TAYLOR
  • MEMBER
  • 2002 CHEVROLET TAHOE
  • 5.3L
  • V8
  • 2WD
  • AUTOMATIC
  • 350,000 MILES
Noticed my A/C had stopped blowing cold. The compressor wasn't coming on. Checked relay and changed low pressure switch near the low side valve. Ended up borrowing gauges and discovered no Freon. Ii ended up changing my Schrader values for both sides, put a vacuum and it held up. Added proper amount of freon and still nothing cold, changed my coil and it started blowing cold, drove home about 2 miles and around the block the next day and all of a sudden I noticed it had stopped blowing cold again. Im still holding freon so currently the compressor isnt coming on, checked my relay switch and its good, im going to get under and check the plug from the relay to make sure its getting power to the coil, belt is still there. Not sure where to go once I do that however.
Monday, May 19th, 2025 AT 12:42 PM

6 Replies

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
You have the right idea, check for power when the engine is running and the A/C system is on. I have seen the compressor coils go bad and not engage when power is applied.

Here is a guide to help:

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

You want to check the Dark green wire at the compressor, let me know :)
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Monday, May 19th, 2025 AT 6:25 PM
Tiny
SHANE TAYLOR
  • MEMBER
  • 22 POSTS
Well, Mr. Ken, I'm thinking somewhere between good lord and wtf I've discovered what may be the problem. This is the coil plug, was completely separated from coil, looks melted maybe but at same time like it got smeared or something. Any ideas as to what happend? Brand new coil severely defective or did something get it too hot? I'm at a loss. But with my luck im not surprised.
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Tuesday, May 20th, 2025 AT 5:54 AM
Tiny
SHANE TAYLOR
  • MEMBER
  • 22 POSTS
I also wonder, does pulling a vacuum drain all oil from compressor, because I was told that only a flush drain oil and not to worry about adding any. I hope I wasn't supposed to and it got so hot it melted wiring for coil. Any way to check oil level without reclaiming freon and all that?
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Tuesday, May 20th, 2025 AT 6:02 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
You are okay, compressor oil will not cause this. There is a high pressure switch at the rear of the compressor, is this where the wire goes? It looks like it came off and got melted by the exhaust manifold.
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Tuesday, May 20th, 2025 AT 9:00 AM
Tiny
SHANE TAYLOR
  • MEMBER
  • 22 POSTS
No that switch is intact, that wire came off the coil. Weird right?
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Tuesday, May 20th, 2025 AT 5:28 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
I see, so this is from the coil itself, if so, it is bad and will need to be replaced. I have never seen that before. First time for everything! If you need help changing it out, please start a new thread.

https://www.2carpros.com/questions/new

Cheers, Ken
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Thursday, May 22nd, 2025 AT 9:54 AM

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